Drycleaning detergent composition



United States Patent Office 3,254,029 Patented May 31, 1966 3 254 029 DRYCLEANING DETEiiGENT COMPOSITION Joseph A. Piepnieyer, Blue Ash, Ohio, assignor to Emery Industries, Inc, Cincinnati, Ohio, a corporation of Ohio N Drawing. Filed Nov. 9, 1961, Ser. No. 151,193

I 2 Claims. (Cl. 252-'152) This application is a continuation-in-part of copending application, Serial No. 729,544 filed April 2, 1958, now abandoned.

This invention relates to a process for treating garments or other articles in chlorinated or petroleum base solvents to remove soil therefrom, a process commonly known as drycleaning, and to a novel detergent composition for use in said process.

In the process of drycleaning, the garments or articles to be cleaned are agitated in the drycleaning solvent which removes oils and greases and simultaneously a large portion of the soil retained in the garments by these oils and greasy materials. The agitation is generally accomplished by inserting the garments in a perforated cylinder which is rotated in the solvent bath. The solvent is usually circulated by means of a pump through a filter which removes the suspended particles of soil. The treatment may last-from to 30 minutes, and at the end of this period, the load is subjected to centrifugal action to remove the excess solvent with the final traces of solvent being removed by a current of warm air which is passed either through a rotating cylinder containing the garments or, in the case of fragile articles, through a drying cabinet.

Various types of equipment are employed in the drycleaning process. In some cases all of the steps are carried out in a single piece of equipment, while in others, such as plants employing petroleum base solvents, the clothes being cleaned may be removed from one piece of equipment to another. In either case, the principles employed are essentially the same.

In modern drycleaning operations it is customary to add from 0.5 to 5% of a drycleaning detergent to the solvent system. These materials have detergent qualities and preferable also have absorbefacient characteristics as well, thus permitting small amounts of water to be evenly distributed in the solvent. The presence of the water improves the detergent action of the bath and at the same time assists in dissipating the static charges which build up on garments as they are tumbled during the drycleaning process, particularly during the drying portion of the cycle. The static charges here referred to are undesirable since they induce .fibers and lint particles from one garment to adhere tenaciously to the surfaces of other garments.

The problem of static build-up was controlled in a generally satisfactory manner by known detergent-containing systems up to the time that nylon and other synthetic fibers came into common use. The static problems encountered in working with these materials are far worse than those presented by natural fibers inasmuch as theformer are hydrophobic in character and thus cannot dissipate their static charge through the medium of water contained in the cleaning solvent.

Attempts have been made to overcome this aggravated static problem by the addition of various types of antistatic agents along with the detergents normally employed. However, anti-static agents are effective only when applied at fairly high concentrations, and inasmuch as solvent systems employed in dry cleaning operations have but a short life, the cost factors are such as to make use of such agents entirely uneconomic.

It is an object of this invention to provide an improved drycleaning process whereby garments made from synthetic fibers, as well as those made from cotton, wool or other natural fibers, may be effectively cleaned without the build-up of static charges.

A further object is to provide a novel composition which exhibits excellent detergent, absorbefacient and anti-static qualities when incorporated in a dry cleaning solvent.

While it is desirable that the material incorporated in the drycleaning solvent possess all of the desirable attributes referred to above, the latter cannot be realized unless the product has the capacity to dissolve readily in each of the solvents conventionally employed in drycleaning operations. Moreover, the material should retain this capacity as it is allowed to stand for considerable periods of time before being used; in other words, the product is preferably one having a high degree of stability. Solvents of the chlorinated hydrocarbon and Stoddard variety pose few problems in this respect since they are capable of dissolving a wide variety of detergent compositions. Such is not the case, however, with many of the special solvents now widely employed in the drycleaning industry. Included in the latter category are, for example, petroleum naphtha cuts of an extremely narrow boiling point range, as well as synthetic, essentially isoparaflinic mixtures as prepared from C and C hydrocarbon starting materials. Accordingly, still another object of this invention is to provide a solvent additive which, in addition to having requisite properties in other respects, is capable of being readily dissolved in all the solvents now in use for dry cleaning purposes.

It has now been found that the foregoing objects are achieved by the use in the drycleaning solvent of a novel composition prepared by firstcondensing a higher fatty acid such as oleic acid, for example, with an alkanolamine, e.g., m0no-, dior triethanolamine. The condensate so formed, along with an excess of the alkano1- amine, is then reacted at elevated temperatures, all as more particularly described below, with an acidic, surface-active agent such as dodecylbenzene sulfonic acid which is capable of forming a salt with the alkanolamine. The composition so formed has good detergent and absorbefacient qualities. Moreover, it has unexpectedly been found that the compositions hereof have a unique static-discharging capacity which is so effective as to substantially eliminate lint problems no matter what type of fabric is being cleaned. Specifically, the electrical conductance of both natural and synthetic fabrics containing only traces of the above described compositions is from 10 to 200 times as great as that of the untreated fabrics.

Products prepared in the manner described herein have good solubility in conventional as well as in special solvents. Moreover, when adjusted in pH so as to be slightly on the acid side, these desired solubility characteristics are retained even after the products have been allowed to stand for many months before being added to the solvent system.

The fatty acid reactant of the present composition, which may be a single acid or mixture of several acids, is one of low or medium titre such as found in coconut oil, tallow, cottonseed oil, soybean oil and tall oil. Oleic acid, or an acid mixture rich therein, is the preferred-reactant, though, in general, good results can be obtained with fatty acids of from l2 to 18 carbon chain length, whether saturated or unsaturated, provided the acid or acid mixture employed has a titre not above 42 C.

The alkanolamine is one of the mono-, dior trialkanolamine variety, wherein each alkanol group contains from 1 to 3 carbon atoms, representative compounds of this class which are useful in a practice of the present invention" being methanolamine, ethanolamine, diethanolamine, triethanolamine, n-propanolamine and N-methylol-ethanolamine. The preferred compositions of this class are the various ethanolamines.

The acidic, surface-active agent employed in forming the novel compositions hereof, is one made by reacting sulfuric acid with an organic compound containing from about 12 to carbon atoms, the compound so obtained being an acid sulfate or a sulfonic acid compound having at least one free acidic hydrogen. The organic reactant is one incorporating an alkyl, alkaryl or aryl grouping, representative compounds of the latter class including lauryl alcohol, oleyl alcohol, myristic alcohol, oleic acid, dodecylbenzene, tridecylbenzene, naphthalene, iso propyl oleate and various straight or branched chain hydrocarbons as derived from petroleum. Typical surface-active agents for use herein include oleyl acid sulfate, lauryl acid sulfate, sulfated isopropyl oleate, oleyl sulfonate, sulfated oleic acid, sulfated castor oil, various petroleum sulfonates, tridecylbenzene sulfonic acid, dodecylbenzene sulfonic acid, nonylbenzene sulfonic acid and nonylnaphthalene sulfonic acid. Of these various compounds, a preferred class for use herein comprises the various alkaryl sulfonic acids and more especially dodecylbenzene sulfonic acid.

As indicated above, the novel compositions of this invention are prepared by first condensing a higher fatty acid with an alkanolamine. These rectants should be combined in a ratio of from about 1 to 3.7 moles of the alkanolamine for each mole of the acid, a preferred practice being to use a slight molar excess of the alkanolamine and in any event not more than about 2 moles thereof for each mole of acid. This condensation reaction is conducted at elevated temperatures of from about 125 to 200 C. until the reaction is completed, heating times of about 2 to 3 hours at temperatures of about 150 to 160 C., for example, usually being satisfactory. Completion of this condensation step is evidenced either by the evolution of water in molar amounts approximately equal to the moles of acid employed, or by a reduction in the free acid content of the mixture to a level below about 4%.

If desired, additional amounts of the alkanolamine up to a total of about 3.7 moles (including that employed in the condensation step) per mole of fatty acid may now be added either with or without further heating of the reaction mixture. In any event, the product should include a total of at least 1.3 moles of the alkanolamine per mole of fatty acid before being reacted with the acidic, surface-active agent in the manner described in the following paragraph.

The condensation product formed between the fatty acid and the alkanolamine is now reacted at temperatures of from about 110 to 175 C. with an acidic, surface-active agent added in an amount suflicient to bring the product to near neutrality, the number of moles of the surface-active agent necessary for this purpose being approximately equal to the total number of moles of alkanolamine employed, less the moles of fatty acid used.

This addition of the surface-active agent may be made at the conclusion of the condensation step either along with any additional alkanolamine then introduced, or simply to the condensation product formed by reacting the fatty acid with a suitable (at least 30% excess of the alkanolamine. In any event, once the surface-active agent has been added, the mixture is heated at a temperature of about 110 to 175 C. for a period of at least 10 minutes, a preferred practice being to heat the mixture for about 0.5 to 2 hours at 125 to 150 C., it having been found that such treatment will normally complete the reaction. Completion of the reaction can be determined analytically if desired, such completion being evident when the amide/ester ratio, as measured by infra-red methods of spectrographic analysis, falls within a range from about 1/1 to 2/1.

A preferred method of operation is to react the fatty acid component with a slight molar excess of the alkanolamine. Once this condensation reaction is complete, there is added to the mixture from about 0.5 to 1 mole of the alkanolamine for each mole thereof previously reacted with the fatty acid. Also added to the mixture at this time is the surface-active agent, the latter being employed in a molar amount approximately equal to the total number of moles of the alkanolamine previously added, less the number of moles of fatty acid employed. The mixture is then heated in the manner described above until the amide/ester ratio falls into the desired range.

The foregoing preparations may be conducted in the presence of an inert solvent such as toluol, if desired, in which event the solvent may be stripped from the final product by distillation in vacuo. No advantage is offered by use of such a solvent, however.

Products prepared in the manner described above will be essentially neutral from the pH standpoint. However, it has been found that while those of the present products which are either neutral or slightly on the alkaline side have good initial solubility in all the various regular and special solvents sold into the drycleaning trade, improved product stability can be obtained by bringing the pH of the product into a range of about 6.3 to 6.8, a pH of about 6.5 being optimum. This adjustment is effected by adding additional amounts of the alkanolamine or of the surface-active agent, as required. The pH can be measured in any convenient fashion, although the practice employed in connection with the examples given below is to measure the pH of a solution containing 5 grams of the product in cc. of a mixture of equal parts of water and of isopropanol. The use of a pH of 7 or above is to be avoided if the product is to retain its good initial solubility characteristics upon being allowed to stand. On the other hand, undue darkening of the material has been found to ensue with age when the pH is brought to levels below about 6.3.

The present invention is illustrated in various of its embodiments by the following:

Example 1 In this operation 0.55 mole of triethanol amine, 0.5 mole of oleic acid and 40 cc. of toluol were mixed and reacted at 150160 C. for three hours. Six cc. of water were collected during this period, and at the end thereof the free oleic acid content of the mixture was 3.7%. To this condensate there was added 0.35 mole of triethanol amine, 12 cc. of water and 0.4 mole of dodecylbenzene sulfonic acid. The mixture was then reacted for one hour at -135 C., during which period 6' cc. of water was collected.

Solvent and residual water were removed by heating under 25 in. vacuum at ISO- C. The resulting product has a pH of 7.3.

A 0.6% solution in Stoddard solvent of the above product was prepared, and to this solution was added 0.2% of water, the later being solubilized as the mixture was agitated. Measurements were then made on the detergency and anti-static qualities of the solution.

The detergency tests were conducted as follows: 100 ml. of the solution was placed in each of two 1 pt. Mason jars containing 25 A" stainless steel balls. In one jar was placed a 4" square of cotton impregnated with 0.1% d-glucose. In the other were placed two fabrics. One was a 4" x 4" W001 flannel swatch, soiled with iron oxide, whose reflectance (degree of darkness) had been measured before and after soiling by means of Reflectometer. The other consisted of a multi-fiber fabric of Orion warp and alternate filling strips of acetate, cotton, nylon, silk, viscose and wool. Both jars were closed and agitated by a launderometer for 30 minutes. The swatches were rinsed and dried. The cotton swatch was analyzed for residual d-glucose. Reflectance of the iron oxide swatch was redetermined to establish the amount of soil removal. Reflectance of the strips in the multifiber swatch was evaluated by comparison with known standards to give a measure of the ability of the detergent to prevent soil redeposition. Results for the iron oxide, and d-glucose tests are expressed as percent of soil re moval. For the multifiber swatch, the results are stated as percent Redeposition (average percent loss in reflectance). The results obtained in the foregoing tests are expressed below in Table I.

TABLE I.PERCENT SOIL REMOVAL, AVERAGE PERCENT Iron oxide 21.8 d-Glucose 34.7 Redeposition 26 The static dissipation properties of the solution were tested in the following manner: Wool and flannel swatches 12" x 4" were impregnated with the solutions and passed between squeeze rolls to give about 0.4% solids on the fabric. The swatches were dried one hour at 70 C., conditioned at least 16 hours at 65% relative humidity 75 F. and tested under the latter conditions. Metal clips 2 /2" wide and 11" apart were attached to the strip and one clip connected to an electrostatic voltmeter. The voltmeter was charged to about 200 volts and the other clip grounded. The time to discharge from 180 volts to 60 volts was only 5 seconds. This compares with times of from about 60 to 500 seconds for tests made under the same conditions with conventional drycleaning detergents.

Example 2 In this operation 0.67 mole of diethanolamine, 0.22 mole of oleic acid and 18 cc. of toluol were mixed. The mixture was reacted for four hours at ISO-160 C., at which time the free fatty acid was found to be 4.1%. To the mixture condensate was added 0.16 mole diethanolamin'e, 0.6 mole d-odecylbenzene sulfonic acid, 18 cc. of water and 100 cc. toluol. The mixture was reacted for one hour at 130-135 C., 23 cc. of Water being collected during the heating period. The mixture was heated at 130140 C. under 25" vacuum to remove solvent and residual water. 5 g. of diethanolamine was added and the mixture stirred thoroughly. The pH was now 7.2.

Detergency and static tests were carried out as described in Example 1. The iron oxide detergency was found to be 26.3, the sugar detergency 29.4, redeposition amounted to only 13%. Static dissipation required less than one second. This example shows that compositions may be employed to provide greater static control at some expense of detergency for those locations or climatic conditions requiring such control.

Example 3 In this operation oleic acid (1 mole) was condensed with diethanolamine (1.1 mole) by heating the mixture at ISO-160 C. for 3-4 hours. At the end of this period approximately 1 mole of water had been distilled from the reaction mixture, and the latter had a free acid content of less than 4%. To the condensate so formed there was added 0.7 mole of diethanolamine and 0.8 mole of dodecylbenzene sulfonic acid. The resulting solution was heated at 130140 C. for 1 hour. The final product so prepared had and amide/ester ratio between about 1.4 and 1.6.

Portions of this product were variously adjusted in pH, the resulting materials having pH values of 6.5, 6.7, 6.8 and 7.0. Tests were then made to determine the solubility of the various products so prepared in a representative special solvent, namely Humble 5105, a synthetic hydrocarbon drycleaning solvent prepared from C and C stocks and marketed by the Humble Oil Company. In making these solubility tests, 60 parts of the product were first combined with 40 parts of Stoddard solvent. One gram of this 60/40 solution Was then added to 100 ml. of the solvent undergoing tests, giving a 0.6% solution if the product in fact formed a clear solution at this concentration level. It is a characteristic of the products of this invention that they dissolve readily in a relatively small amount of a given solvent, but tend to separate out (as manifested by the appearance of turbidity in the solution) as larger quantities of the solvent are added. Since it is desirable that the product provide a clear solution even when employed in amounts as low as 0.1 or 0.2%, the 0.6% solution as first prepared is progressively diluted with larger and larger quantities of the solvent until the solution becomes turbid. If the product does not dissolve to the extent of at least 0.6%, it is regarded as being insoluble in the particular solvent employed. The solubility data given in Table II below indicate the ml. of solvent that can be added to 100 ml. of 0.6% solution before the latter becomes turbid.

TABLE II.SOLUBILITY OF PRODUCT IN HUMBLE 5-10-5 SOLVENT Solubility (ml. to turbidity) Adjusted pH 01' product As initially After standing prepared days 73 days The foregoing products were found to be soluble in substantially all proportions (whether fresh or aged for many months) in Stoddard solvent and perchlorethylene. However, as evidenced by the data of the foregoing table, control of pH to a level of approximately 6.5 is important if the aged product is to have the desired solubility characteristics in special solvents. The pH valueisless important when dealing with the freshly prepared materials, though even here those products which were slightly on the acid side afforded a higher dilution factor in the special solvent before becoming turbid.

Example 4 The operations here reported do not exemplify the invention 'but are incorporated for comparative purposes.

(a) The preparation of Example 3 was repeated except that here the heating step following addition of diethanolamine and dodecylbenzene sulfon-ic .acid to the condensate was omitted. Instead, the reaction mixture, which warmed with the addition of the latter ingredients, was allowed to stand for several hours without any application of external heat. The resulting product, even when adjusted in pH to optimum levels, was found to be insoluble in the Humble 5-10-5 solvent as well as in Apco 125, the latter being a narrow-boiling, depolarized hydrocarbon fraction marketed by Anderson-Pritchard Company. This lack of solubility in special solvents was manifested by the product in both the freshly prepared as well as in the aged condition.

(b) Instead of first forming the condensate and then heating the latter with excess alkanolamine and a surface-active agent as described in Example 3, the several reagents (1 mole oleic acid, 1.8 moles diethanolamine and 0.8 mole dodecylbenzene sulfonic acid) were combined into a single reaction mixture and then heated to a temperature of 150170 C. for about 4 hours, heating being discontinued when approximately one mole of water had been distilled from the mixture. The product so obtained had an amide/ester ratio falling in a range of from 1/ l to 2/1. The color of the product was that of dark mahogany, this in contrast to the straw color of the EX- ample 3 product. Moreover, the product obtained by this single heating treatment was found to be insoluble in various of the special solvents commonly employed, including Apco and Humble 5-105.

Example In this operation the procedure of Example 3 was repeated except that here all of the diethanolamine (1.8 moles) was added at the time of condensing the alkanolamine with 1 mole of oleic acid. The product so obtained was found to be soluble in Apco 125, clear solutions of a concentration of 0.1% being readily obtained. However, in the case of other special solvents such as Humble 5-10-5, turbidity developed after 60 ml, of the solvent has been added to ml. of the 0.6% solution. The color of this product was much darker than that obtained in the Example 3 procedure Where the alkanolamine condensed with the oleic acid represented only a slight (10% molar excess.

Example 6 The preparation of Example 3 is repeated, but with the dodecycltbenzene sulfonic acid being replaced in the one case by tridecylbenzene sulfonic acid, and, in the other, by nonylbenzene sulfonic acid. The resulting products are considered to have substantially the same qualities and characteristics as the Example 3 material.

Example 7 The preparation of Example 3 is repeated, but with the dodecybenzene sulfonic acid being replaced by an equivalent amount of petroleum sulfonic acid (petronic acid). The product so obtained is considered to have good solubility but somewhat poorer detergency qualities than the Example 3 material.

Example 8 The process of Example 3 is repeated, but with the 0.7 mole of diethanolamine added in the second stage being replaced, in turn, by equivalent amounts of diisopropanolamine, monoisopropanolamine and monoethanolamine. The resulting products all have good solubility characteristics, though that prepared from diisopropanolamine had somewhat poorer solubility than the other products.

I claim:

1. A drycleaning detergent composition prepared by first reacting a fatty acid material made up of fatty acids of from 12 to 18 carbon atoms and having a titre not exceeding about 42 C., with an alkanolamine wherein the alkanol groups each contain from 1 to 3 carbon atoms, said reactants being employed in a ratio of from about 1 to 3.7 moles of the alkanolamine per mole of fatty acid, and being heated at temperatures of from about to 200 C. until the reaction formative of an alkanolaminefatty acid condensation product is substantially complete; adding to said condensation product any further amount of said alkanolamine as required to bring the total amount thereof employed to between 1.3 and 3.7 moles per mole of said fatty acid material, and also adding to said condensation product an acidic surface active agent having from 12 to 20 carbon atoms selected from the group consisting of alkyl sulfuric acids, and alkyl benzene and alkyl naphthalene sulfonic acids said surface-active agent being added in an amount sufiicient to bring the product to near neutrality; and heating the resulting reaction mixture at a temperature of from about 110 to C. until the amide/ester ratio of the product is between about 1/1 and 2/ 1.

2. A drycleaning detergent composition as recited in claim 1, wherein the final reaction product is adjusted in pH to a level between about 6.3 and 6.8.

References Cited by the Examiner UNITED STATES PATENTS 2,158,614 5/1939 Reddish 8142 2,599,391 6/1952 Katzman 8142 2,729,576 1/1956 Trusler 25289 2,757,143 7/1956 Katzman 252-453 2,768,957 10/1956 Sullivan et a1 252--153 2,826,596 3/1958 Maher 252152 FOREIGN PATENTS 706,570 3/1954 Great Britain.

JULIUS GREENWALD, Primary Examiner. 

1. A DRYCLEANING DETERGENT COMPOSITION PREPARED BY FIRST REACTING A FATTY ACID MATERIAL MADE UP OF FATTY ACIDS OF FROM 12 TO 18 CARBON ATOMS AND HAVING A TITRE NOT EXCEEDING ABOUT 42*C., WITH AN ALKANOLAMINE WHEREIN THE ALKANOL GROUPS EACH CONTAIN FROM 1 TO 3 CARBON ATOMS, SAID REACTANTS BEING EMPLOYED IN A RATIO OF FROM ABOUT 1 TO 3.7 MOLES OF THE ALKANOLAMINE PER MOLE OF FATTY ACID, AND BEING HEATED AT TEMPERATURES OF FROM ABOUT 125 TO 200*C. UNTIL THE REACTION FORMATIVE OF AN ALKANOLAMINEFATTY ACID CONDENSATION PRODUCT IS SUBSTANTIALLY COMPLETE; ADDING TO SAID CONDENSATION PRODUCT ANY FURTHER AMOUNT OF SAID ALKANOLAMINE AS REQUIRED TO BRING THE TOTAL AMOUNT THEREOF EMPLOYED TO BETWEEN 1.3 AND 3.7 MOLES PER MOLE OF SAID FATTY ACID MATERIAL, AND ALSO ADDING TO SAID CONDENSATION PRODUCT AN ACIDIC SURFACE ACTIVE AGENT HAVING FROM 12 TO 20 CARBON ATOMS SELECTED FROM THE GROUP CONSISTING OF ALKYL SULFURIC ACIDS, AND ALKYL BENZENE AND ALKYL NAPHTHALENE SULFONIC ACIDS SAID SURFACE-ACTIVE AGENT BEING ADDED IN AN AMOUNT SUFFICIENT TO BRING THE PRODUCT TO NEAR NEUTRALITY; AND HEATING THE RESULTING REACTION MIXTURE AT A TEMPERATURE OF FROM ABOUT 110 TO 175*C. UNTIL THE AMIDE/ESTER RATIO OF THE PRODUCT IS BETWEEN ABOUT 1/1 AND 2/1. 